NZJFS - Volume 42 (2012)

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  Estimating carbon stocks in stands of Podocarpus cunninghamii in the eastern South Island high country of New Zealand

  Williams, A., & Norton, D. A.
  

  Williams and Norton (pp. 29-38) provide the first estimates of existing above- and below-ground carbon stocks in high country stands of Podocarpus cunninghamii and present a preliminary model of Podocarpus cunninghamii carbon sequestration rate.

  07/02/2012. 29-38.
  ISSN 1179-5395. [749.7 KB].

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  The Land-Use, Land-Use Change and Forestry (LULUCF) sector of the Kyoto Protocol requires New Zealand to monitor changes in the country’s carbon stocks, including those within indigenous forests. Podocarpus cunninghamii Colenso was, in pre-human times, a dominant tree species within the forests of the South Island high country. Anthropogenic disturbance, primarily fire, has converted most of these forests to grassland. Despite this mass deforestation, remnant stands of Podocarpus cunninghamii still exist, and may represent important point sinks of carbon. This study provides first estimates of existing above- and below-ground carbon stocks in high country stands of Podocarpus cunninghamii and presents a preliminary model of Podocarpus cunninghamii carbon sequestration rate. Carbon stocks within high country stands of Podocarpus cunninghamii range from 7.3 t ha^-1 in the drylands to 130.1 t ha^-1 in the wetter areas. Estimates based on tree ring widths indicate a high country-wide Podocarpus cunninghamii carbon sequestration rate of 0.1 - 0.5 t ha^-1 yr^-1 for 250 - 1000 stems ha^-1, respectively.
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  Validation of an individual-tree volume equation for Nothofagus menziesii (Hook f.) Oerst in Southland, New Zealand.

  Mason, E. G., Sewell, A. C., & Evison, D.
  

  Mason et al. (pp. 25-28) tested the validity of a generalised individual-tree volume equation specifically for Nothofagus menziesii. The correlation between predicted and estimated volumes was 0.97.

  20/01/2012. 25-28.
  ISSN 1179-5395. [565.5 KB].

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  A tree volume equation for New Zealand’s Nothofagus species was validated using sectional measurements from Nothofagus menziesii (Hook f.) Oerst trees at Alton Valley in Southland. Upper stem diameters of 60 trees were measured using a Tele-Relaskop within three plots that had been thinned to stockings of 150, 1500 and 8228 stems ha^-1. Bark thickness measurements were obtained from a range of heights up tree stems. Merchantable under-bark volumes of stems calculated from sectional measurement were compared with merchantable volumes predicted by a model developed by Ellis (1979). The model was found to predict volumes with minimal bias even though errors were kurtotic and a little outside the range predicted. The correlation between predicted and estimated volumes was 0.97.
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  Rearing and storing Arhopalus ferus life stages in the laboratory for experimental purposes.

  van Epenhuijsen, C. W., Somerfield, K. G., & Hedderley, D.
  

  The quality and exportability of radiata pine logs can be adversely affected by burnt pine longhorn beetle infestation. Van Epenhuijsen et al. (pp. 15-23) found suitable conditions for storing eggs, for storing live adults, and for rearing larvae of this pest for use in fumigation trials.

  18/01/2012. 15-23.
  ISSN 1179-5395. [773.3 KB].

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  It can be difficult to provide large numbers of fresh forest insects for use in fumigation experiments. This paper reports on studies aimed at providing large numbers of fresh burnt pine longhorn beetles (Arhopalus ferus Mulsant) (Coleoptera: Cerambycidae). Burnt pine longhorn beetle is one of the most important pests of quarantine concern associated with export of New Zealand radiata (Pinus radiata D.Don) logs, particularly to India, China and other Asian countries.

  The timing of the collection of hundreds of adults, obtaining eggs from them and then storing the eggs for use in fumigation trials must be synchronised with the timing of the trial itself. Three separate experiments were conducted to improve rearing and storage of burnt pine longhorn beetles. In the first experiment, burnt pine longhorn beetle eggs were laid by field-collected adults. Larvae were successfully reared on an artificial (huhu) diet at 20 °C ± 1.5 °C and pupated after 216 days (males) and 227 days (females). Adults emerged after a further 2.5 weeks. These adults stayed alive in the laboratory for up to 46 days at 20 °C. In a second experiment field-collected burnt pine longhorn beetle adults of mixed age were stored at 4, 6, 8, 10, 12 and 14 °C for up to 10 weeks. The longest survival time was at 6 °C (50% still alive after 28 days). In a third study we found 12 - 14 °C was the best temperature for storing eggs. The total life times, times to pupation and adult survival times were not significantly different between males and females. Males tended to be more variable than females particularly in the time spent as larvae and as adults.
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  Maps and models of density and stiffness within individual Douglas-fir trees.

  Todoroki, C. L., Lowell, E. C., Dykstra, D., & Briggs, D. G.
  

  Todoroki et al. (pp. 1-13) developed spatial maps of density and stiffness patterns within individual Douglas-fir trees that could be used to predict within-tree wood properties using easily measurable tree variables.

  10/01/2012. 1-13.
  ISSN 1179-5395. [964.0 KB].

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  Spatial maps of density and stiffness patterns within individual trees were developed using two methods: (1) measured wood properties of veneer sheets; and (2) mixed effects models, to test the hypothesis that within-tree patterns could be predicted from easily measurable tree variables (height, taper, breast-height diameter, and acoustic velocity).

  Sample trees comprised an assortment of 25 coastal Pacific Northwest Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) trees grown on three sites under a range of thinning regimes. At harvest, trees were 36 years old on one site, and 45 and 51 on the other two. After felling and crosscutting, bolts were peeled into veneer, labelled, dried, weighed, measured, and non-destructively tested using a Metriguard 2600^TM veneer tester. The labels allowed each sheet to be tracked back to the peeler bolt and consequently to the position within the parent tree from which it came, and the measurements allowed calculation of veneer density and, after application of the fundamental equation for propagation of sound, veneer stiffness.

  Maps of each parent tree created from the veneer data clearly demonstrated regions of higher density and stiffness. Furthermore, within each tree, density was approximately normally distributed, while stiffness tended to have moderate negative skew. Maps developed using mixed effects models showed very good correspondence between measured and predicted patterns, particularly for density. Despite differences in age, site and silviculture, results from this study suggest that it is possible to predict within-tree wood properties using easily measurable tree variables.